Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile machine.
Description of the Related Art
Conventionally, image forming apparatuses such as copying machines, printers, and facsimile machines perform control to decrease wind noise of a cooling fan by operating the cooling fan only when it is needed with the view to decrease operation noise. For example, Japanese Patent Laid-Open No. 2008-242488 decreases the wind noise of a plurality of cooling fans by controlling ON/OFF and the numbers of revolutions of the cooling fans according to the temperature of a fixing device.
Further, Japanese Patent Laid-Open No. 02-214871 suppresses generation of noise by switching operations or the numbers of revolutions of the cooling fans according to the number of copied sheets.
In recent years, models of a wide-range of image forming apparatuses that realize a plurality of productivities while increasing development efficiency by sharing a mechanical configuration and the like have become the mainstream. In such models of image forming apparatuses, a model of an image forming apparatus with a lower productivity is less easily increased in the temperature in the apparatus than a model of an image forming apparatus with a higher productivity, and thus requires less cooling by the cooling fans. However, conventionally, the cooling by the cooling fans necessary for the model of the image forming apparatus with a higher productivity has also been performed in the model of the image forming apparatus with a lower productivity, and thus the wind noise of the cooling fans has been noticeable.
In the models of the wide-range image forming apparatuses with a plurality of productivities and sharing the mechanical configuration, the model of the image forming apparatus with a lower productivity has smaller operation noise of drive systems because motor speeds of the drive systems are slower than those of the model of the image forming apparatus with a higher productivity. Meanwhile, as for the cooling fans, the model of the image forming apparatus with a lower productivity and the model of the image forming apparatus with a higher productivity have equivalent numbers of revolutions. Therefore, there is a problem that the entire operation noise of the mode of the image forming apparatus with a lower productivity is not substantially different from that of the model of the image forming apparatus with a higher productivity.